This invention relates generally to electrical control systems, and more specifically to an aircraft electrical control system which disconnects power to a load when a current imbalance is sensed.
In the electromechanical arts, current imbalances are serious problems that can lead to disastrous results, such as arcing within fuel pumps. Arcing within a fuel pump can lead to a breach of the fuel vessel. In aircraft, such a breach can be catastrophic. Thus, a device or methodology is needed that can suppress this type of arcing, as well as other associated problems. Presently, a common type of current protection device being utilized in aircraft is a thermal circuit breaker. However, arcing typically does not cause thermal circuit breakers to activate. There thus exists a need for an improved ground fault circuit interrupter device, particularly for aircraft. The present invention addresses these and other concerns.
The present invention is directed towards a ground fault circuit interrupter particularly attractive for use in aircraft for interrupting a circuit having a line side and a load side. The ground fault circuit interrupter can be retrofit to existing aircraft, or can be utilized in newly constructed aircraft and new aircraft designs. The aircraft applicable ground fault circuit interrupter includes a power supply, a circuit to be monitored, a sensor, a logic controller, and a power controller. The power supply is configured to provide power to the sensor and logic controller. A second power supply may optionally be provided to power the power controller. The sensor is configured to sense a current imbalance in the line side of the circuit to be monitored. The logic controller is configured to process input from the sensor. In a presently preferred embodiment, the logic controller compares the sensor signal with a range of sensor signals representing acceptable operation and outputs a signal representing a circuit current imbalance when the sensor signal is outside the acceptable range of signals. The power controller is configured to receive input from the logic controller and remove power to the load side of the circuit when a current imbalance is sensed. In a presently preferred embodiment, the power removal from the load side of the circuit due to a sensed current imbalance is maintained until the power source is cycled.
The present invention also provides for a method for interrupting an electrical circuit for an electrical load, the electrical circuit having a line side and a load side with a ground fault. Briefly, the method comprises providing a supply of power, continually monitoring the circuit for a current imbalance, sensing a current imbalance in the line side of the circuit, processing input from a power supply and a sensor, receiving input from a logic controller, and interrupting the circuit when a current imbalance is sensed. In one presently preferred aspect, interrupting of the circuit when a current imbalance is sensed is maintained until the power source is cycled. Typically, the load being supplied by the current is a motor. In another preferred aspect, no additional signals, inputs, or sources of power are required. In one presently preferred use of the method, the load side of the circuit is connected to a fuel pump, and arcing is suppressed within the fuel pump.
Other features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.